Apparatus and method for overhead cable towed sports

ABSTRACT

An elevated loop of cable or other flexible traction member extends suspended above a surface over which a sport participant is to be towed. The loop includes upper and lower legs which run between a pair of pulleys which are mounted for rotation in substantially vertical planes atop respective ones of a pair of mutually separated support structures. At least one of the pulleys is coupled to a reversible, variable speed drive. A carrier is coupled to one leg of the loop and in response to rotation of the drive, unit travels along according to a reversible variable speed velocity profile.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119(e) to commonlyowned co-pending U.S. Provisional Application Ser. No. 61/241,824 filedSep. 11, 2009 for all commonly disclosed subject matter.

STATEMENT REGARDING FEDERALLY SPONSORED-RESEARCH OR DEVELOPMENT

Not Applicable.

INCORPORATION BY REFERENCE

U.S. Provisional Application Ser. No. 61/241,824 is expresslyincorporated herein by reference in its entirety to form part of thepresent disclosure.

FIELD OF THE INVENTION

The invention relates to the field of overhead cable towed sports,namely, competitive or recreational sports of the type in which aparticipant is towed over a surface by way of a tow line which dependsfrom a movably driven overhead cable. More particularly, the presentinvention relates to an apparatus and method for propelling snow skiers,snow boarders, riders of tubes or other inflatables, water skiers, wakeboarders, knee boarders, ice skaters or other participants in towedsports and recreations, back and forth one or more times over a surfaceof land and/or water via a tow line, one end of which is coupled to amovable carrier mounted on an elevated, reversibly drivable, loop ofcable which extends between a pair of mutually-spaced, substantiallyvertically oriented pulleys.

BACKGROUND OF THE INVENTION

As contrasted with overhead cable towed sports, which utilize a poweredoverhead cable to provide towed propulsion of a participant duringexecution of sport itself, various cable powered conveyances fortransporting participants to a location from whence they may disembarkthe conveyance to pursue a sport in the course of which they arepropelled other than by a cable have been known in the prior art. Forexample, snow skiers and snow boarders are propelled downhill by gravitythough it has long been known in the prior art to use power drivenmechanical devices to transport them uphill. Various conveyances whichutilize one or more power driven cables have been used for transportingsnow skiers and snow boarders back up a slope to a location from whichthey may disembark and glide freely downhill propelled only by gravity.A simple form of such a transportation device, commonly referred to as a“rope tow”, includes an endless rope which engages a drive pulley whichis coupled to a motive power source such as an electric motor orcombustion engine. A skier grasps the moving rope to be hauled uphill,gliding on their skies then releases the rope upon reaching an upslopelocation from which they wish to begin their downhill run.

U.S. Pat. No. 4,047,487 to Wyss describes a towing mechanism for a skilift of the type wherein an upright snow skier may be propelled uphillwith skies remaining in contact with the snow cover by grasping andleaning on a towing bar which is coupled to a linearly travelingoverhead hauling cable by way of a tow rope extending retractably from amechanism which is connected to the hauling cable by way of asuspension. Since the skier is able to lean against the low bar, thistype of ski lift is somewhat less tiring and easier to use than a basicrope tow. Even easier to use, and less physically demanding of theskier, are ski lifts of the type generally referred to as “chair lifts”.For example, U.S. Pat. No. 2,582,201 to Huntington describes a ski liftin which skiers ride uphill while seated in a chair suspended from anoverhead cable. With such a device, the skis of the skier typicallyremain suspended in the air until the skier disembarks the lift.

While riding a ski lift such as any of the types described above mightbe regarded as “recreational” or even “sporting” in some sense, the truesport or recreation pursued by their users, namely, downhill skiing,begins only after the ride on the ski lift has ended. The conventionalski lift is merely a mode of transporting snow skiers uphill using acable to a location from which they can ski downward. As contrasted withthe use of a cable to merely transport a person to a location from whichthey could pursue a sport or recreation, German inventor Bruno Rixenpioneered the first true cable towed sport in the early 1960's, namely,cable waterskiing.

U.S. Pat. Nos. 3,743,278 and 3,838,647, both to Rixen, disclose anapparatus for towing a water skier under motive power provided by a pairof mutually-spaced, parallel overhead cables arranged to define a closedloop circuit suspended above the surface of a body of water. Asdisclosed for example in Rixen '647 and represented in prior art FIGS. 1and 2 hereof, a pair of endless cables 302 and 303, are driven to movecontinuously in one direction 352 at a constant speed around acontinuous closed circuit 390 whose corner boundaries are established bypairs of pulleys. Although a triangular shaped closed circuit could beestablished using only three (3) pulley pairs, in the example of FIG. 1,four (4) pulley pairs 305, 306, 307 and 308 are used to form a generallyquadrilateral shaped closed circuit. The two (2) pulleys making uppulley pair 305 serve as drive pulleys and the other pulley pairs serveas guide pulleys which, as shown in FIG. 2, are each mounted on a mast310 stayed by guy wires 314 in order support cables 302 and 303 suchthat they are positioned elevated well above the surface 312A of awaterway 312. As illustrated in FIG. 2 with respect to guide pulley pair308 which is typical, each guide pulley pair 306, 307 and 308 consistsof a pair of horizontally oriented pulleys 308A and 308B of equaldiameter mounted for rotation in a horizontal plane on a common,vertically oriented, shaft 308C, with upper pulley 308A being locateddirectly above, and running generally parallel to, lower pulley 308B tosupport upper cable 302 directly above lower cable 303.

The drive pulley pair 305 consists of an upper drive pulley and a lowerdrive pulley which are mounted for rotation about a common vertical axisin parallel horizontal planes. The upper drive pulley and the lowerdrive pulley are both mounted to coaxial vertically-oriented stub shaftsof a conventional automotive differential which is drivably coupled, byway of a belt or a chain 345, to a prime mover, such as an engine 348mounted on a horizontally extending frame member 338 which also supportsthe drive pulley pair 305 and is itself supported by a mast 339 whichsupports the drive pulley pair 305 at a elevated location above thewater surface 312.

Attached securely to the parallel upper and lower cables 302, 303 areone or more mutually spaced traction devices 301 which travelcontinuously with cables 302 and 303 in direction 352, around the closedloop circuit passing around the rear outside portions of each of pulleypairs 305, 306, 307, 308 as they do so. Each traction device 301includes a releasable clamp 400, which permits the selective attachmentand detachment of the end of a tow lie 355 whose opposite end iscoupled, by way of a bridle formed by loop members 377, 388 to the endsof a handle bar 366, which may be grasped by a person “P” to be towedwearing water skis “S” or riding a wake board (not shown). A launchingarea 354, which may be located on the bank 311 of waterway 312 is spaceda distance laterally from the cables 302, 303 and positioned such thatthe tow line 355 can be maintained in a taut condition to accelerate askier leaving the launching area 354 relatively smoothly from astandstill and increasing in speed until reaching the constant speed ofthe traction device 301 and cables 302, 303.

Although prior art cable tow ski systems similar to those which havejust been described with reference to FIGS. 1 and 2 have been relativelysuccessful, they also suffer from a number of significant drawbacks andlimitations. Because they require the upper and lower cables 302, 303 tobe routed to form a continuous closed loop circuit whose cornerboundaries are established by the locations of the horizontal pulleypairs, including not only drive pulley pair 305, but also at least twoor more guide pulley pairs, a relatively large area of usable watersurface is required in order to implement such a system. Moreover, suchsystems require a minimum of six (6) or more individual pulleys, a masttower or other support structure to support each one of at least threepulley pairs and two drive cables of sufficient length to define theclosed circuit. Accordingly, closed circuit cable tow systems require alarge capital investment not only for a suitably large site but also tomanufacture, install and maintain. Among the significant maintenanceissues which are acute in such prior art systems are those associatedwith stretch and wear of the drive cables and the pulleys. Cable stretchis typically expressed in units of length per unit of overall length ofthe cable. That is, under a given sufficient tension, a cable of longeroverall length will tend to increase its total length more than anotherwise identical cable which is shorter. Likewise, increases anddecreases of cable length due to thermal expansion and contractionresulting from ambient temperature variations and heat generated byfriction are more pronounced in the longer cables which closed circuitcable tow systems tend to require.

In closed circuit cable tow systems of the type described above, thecables 302 and 303 are fitted with connectors necessary for securing thetraction devices 301 to those cables. Those portions of the cable fittedwith such connectors tend to create nonuniformities in the manner inwhich they pass over the pulleys as compared to the areas of the cablebetween the connectors. Since each of those connectors passes overmultiple horizontal pulleys in the course or every orbit of everytraction device 301 around the closed circuit, unless great care istaken, such non uniformities can give rise to accelerated wear andrepeated impact forces and vibration which could tend to cause parts toloosen or other undesired effects.

Because the pulleys in the pulley pairs 305, 306, 307, and 308 of theprior art systems described above rotate in horizontal planes, aboutvertical axes, a disproportionately large share of the mechanical loadon each pulley due to the weight of the drive cables 302 and 303 iscarried on one side of the vertical axis of rotation of each pulley.This uneven loading concentrates the effects of friction, heating andwear on the relatively thin, and thus potentially structurallyvulnerable, lower walls of the peripheral grooved portions of thepulleys and on the lower sides of the drive cables themselves. It canalso be appreciated that in the event one or both cables 302 and 303were to fall as a result of cable failure, pulley failure and/orexcessive stretch or thermal expansion of the cables, a serious safetyhazard to skiers, bystanders and/or operators of the system couldresult. The uneven loading which results from the pulleys being mountedfor rotation about vertical axes also generates undesirable lateralloads on the shafts and bearings which support the pulleys and tends tocause increased friction, accelerated mechanical wear, reduced operatingenergy efficiency, decreased component life and increased maintenanceand operating expenses.

Another significant limitation of the cable tow ski systems of Rixen'278 and '647 is that the drive cables 302, 303 run at a constant speedand in order to launch skiers from a standstill without excessivejerking of the tow line 355, the length of the tow line, and thedistance and relative angle between the cable and the location fromwhich skiers are launched are dependant upon the speed of the cables andnot amenable to easy variation. As a consequence, such systems aredifficult to adapt to participants of varying skill levels and provide aride experience which can quickly become monotonous and uninteresting.

In view of the foregoing, it is an object of the invention to provide atowed sports apparatus and method which is less costly to implement,operate and maintain than those of the prior art.

It is a further object of the invention to provide a towed sportsapparatus and method which can provide a participant with a continuousride of indefinite desired duration yet can be implemented on eitherlarge or relatively small tracts of land and/or water.

It is a further object of the invention to provide a towed sportsapparatus and method capable of providing an interesting and readilychangeable ride experience appropriate to participants whose skilllevels may range from beginner to world class competitor.

It is a further object of the invention to provide a towed sportsapparatus and method capable of providing a ride experience which mayconsist of, or include, either: a one way ride across a surfacebeginning from a standstill at one side with the rider ending stopped atthe opposite side or an intermediate location; a two-way back and forthride across a surface, with the rider both beginning and ending the ridefrom a stop on one side; and/or a continuous, multiple back and forthride, of indefinite desired duration, which may begin and/or end at anarbitrary location on or between the two sides.

It is a further object of the invention of provide a towed sportsapparatus which may be constructed as either a substantially permanentinstallation or one which is portable and capable of being erectedquickly and simply at a given site then dismantled with comparable easefor transport and erection at a different site.

SUMMARY OF THE INVENTION

Rather than the prior art approach of using three or more pairs ofpulleys rotating in horizontal planes to define the corners of acontinuous, closed circuit having two cables driven in the samerotational direction at constant speed, a preferred embodiment of theapparatus of the invention contemplates use of a directionallyreversibly drivable loop of a flexible traction member, such as a cable,suspended overhead between a pair of pulleys which rotate insubstantially vertical planes about substantially horizontal axes. Eachof the pulleys is supported above the elevation of riding surface by arespective one of a pair of mutually spaced support structures. One ofthe support structures carries a motor driven, substantially verticallyoriented drive pulley and the other support structure carries anon-driven, substantially vertically oriented deflection pulley.Preferably, the two pulleys are aligned such that their respectivesubstantially vertical planes of rotation are co-planar, or at leastsubstantially co-planer. Also, the respective substantially horizontalrotational axes of the two pulleys are preferably substantially parallelwith one another and substantially co-planar with one another. The loopof cable has an upper leg and a lower leg. The upper and lower legs ofthe loop run generally parallel to one another in the region between thetwo pulleys and move in generally opposite linear directions, regardlessof whether the loop is driven in a clockwise or counterclockwiserotational direction. With the two pulleys being substantiallyvertically oriented and aligned with one another such that the upper legand the lower leg of the will also lie in a common, substantiallyvertical plane under quiescent conditions when the loop is still and notbeing subjected to external forces such as wind or tension transmittedby way of the tow line. A movable carrier is mechanically coupledbetween the upper leg and the lower leg of the loop. In a preferredembodiment the carrier is affixed to the lower leg and has rollers whichallow it to move linearly along the upper leg. A tow line depends from alower portion of the carrier assembly and is attached to a handle whichis graspable by the sport participant.

As the drive pulley is driven in one rotational direction by a drivewhich preferably includes a variable speed motor under the control of amotor controller, rotation of the loop in a first rotational directioncauses the carrier assembly to be driven along the loop in a firstlinear direction headed generally away from the first support structureand toward the second support structure. On the other hand, when thedrive pulley is driven in a second, opposite, rotational direction, thecarrier assembly is driven oppositely along the loop, in a second lineardirection which is opposite the first linear direction that is, adirection headed generally away from the second support structure andtoward the first support structure. The participant is towed accordingto a vector, a component of which is oriented in either the first orsecond linear directions, depending on the direction of linear travel ofthe carrier assembly but it is to be appreciated that the participant isnot limited to moving in a linear motion but can execute turns, jumps,or other complex maneuvers along the way, according to their desire andability. It is also to be appreciated that the participant need not belimited to a one-way ride or to a single back and forth ride.

Although the invention offers the flexibility to provide one-way rides,and/or two-way, single back and forth rides, as may be desired, it alsoallows a participant to ride continuously back and forth, being towed byreciprocating movement of the carrier back and forth multiple times,along or between virtually any desired portion(s) of the loop to providea continuous ride of indefinite duration. Moreover, such rides may beginand end at respective start and end locations which can be locatedsubstantially arbitrarily, at any safe location within reach of the towline. Moreover, none of the modes of operation just described arerestricted to a constant speed or to an increase in speed only at thestart of a ride.

According to a preferred embodiment of the apparatus and method of theinvention, the drive which drives the drive pulley is a drive is bothreversible and speed variable. Thus, the loop and the carrier assemblycan be driven at a velocity which can be set or changed as desired toassume substantially any desired magnitude within a range of speedsand/or execute reversals of direction of the carrier at any point duringa ride. Such velocity control can optionally be carried out onpre-programmed basis, such as by causing the motor controller to executea series of instructions which may either be stored in a local memorydevice or downloaded from a computer network or portable machinereadable storage media. According to one preferred embodiment, aparticipant is towed according to a velocity profile which ramps up,that is, increases in speed, at least once, and ramps down, that is,decreases in speed, at least once between each reversal of 0000directionof the carrier.

According to a further aspect of certain preferred embodiments of theapparatus and method of the invention, between reversals of lineardirection, the carrier stops, or at least substantially slows, andeither remains completely stopped or substantially slowed, or at leastdoes not resume movement at more than a particular speed, for a certaindwell interval between reversals of direction of the carrier. Thisallows the participant to execute, or at least partially execute, a turnbefore the carrier itself begins its reverse travel thereby avoidingundue tension on the tow line which could otherwise cause theparticipant to be injured or lose their grip.

According to yet a further aspect of the invention, in normal operation,neither the carrier itself, nor any connector or other member attachingthe carrier to the traction member, passes over any portion of either ofthe substantially vertical pulleys. The drive is preferably controlledto prevent the carrier from coming into contact with either of thevertical pulleys in normal operation and is most preferably controlledso as to maintain at least a minimum clearance distance between thecarrier and each of the substantially vertical pulleys at all timesduring normal operation.

According to another aspect of the invention, a mechanical guard isphysically interposed between the carrier and each of the substantiallyvertical pulleys to act as a barrier to prevent the carrier from cominginto contact with either of the substantially vertical pulleys in theevent of a malfunction or failure which might for any reason cause thecarrier not to stop short prior to encountering the mechanical guard.

According to yet a further aspect of the invention, the instantaneousspeed and/or direction of the carrier can be controlled remotely underthe control of an operator or some other person, by means of a wired orwireless remote control unit. In the case of a wireless remote control,even the participant themselves can exercise such control over their ownride while the ride is in progress. Such control can be carried out on asubstantially real-time basis, or subject to a set or variable delayoccurring between a change in a control input and the resulting responseto that change being reflected in the actual velocity of the carrier inorder to allow the rider some time to anticipate the change.

These and other objects and advantages of the present invention will bemade clear to a person of ordinary skill in the art upon review of thefollowing detailed description of preferred embodiments taken inconjunction with the appended drawings in which like reference numeralsare used to indicate like items.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view illustrating a power driven cable water skitow apparatus according to the prior art;

FIG. 2 is a side elevational view taken along line 2-2 of FIG. 1,further illustrating the prior art power driven cable water ski towapparatus of FIG. 1;

FIG. 3 is a perspective view of a preferred embodiment of the apparatusof the invention shown in use towing a participant, in this case by wayof example, a wake boarder;

FIG. 4 is a side elevational view of the embodiment of FIG. 3;

FIG. 5 is a view taken along line 5-5 of FIG. 3;

FIG. 5A is a side elevational view along line 5A-5A of FIG. 6.

FIG. 6 is top plan view of the embodiment of FIG. 3;

FIG. 7 is a view taken along line 7-7 of FIG. 3;

FIG. 8 is perspective view illustrating further details of the drive ofthe embodiment of FIG. 3;

FIG. 9 is perspective view illustrating further details of the mountingof the deflection pulley of the embodiment of FIG. 3;

FIG. 10 is perspective view illustrating further details of the carrierof the embodiment of FIG. 3;

FIG. 11 is graph of speed versus time illustrating examples of variousvelocity profiles which can be carried out according to certain aspectsof the method of the invention;

FIG. 12 is a side elevational view illustrating an alternative form ofcarrier.

FIG. 13 is a perspective view further illustrating the alternativecarrier shown in FIG. 12.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

A preferred embodiment of a cable tow apparatus 10 for use in overheadcable towed sports is schematically illustrated in FIG. 3. Apparatus 10includes a first support structure 12 and a second support structure 14which are mutually spaced from one another across at least a portion ofa surface 16 over which a sport participant 120 is to be towed by way ofa tow line 26. By way of non-limiting example, surface 16 is illustratedin FIG. 3 as being a portion of a stream or river that is bounded onopposite sides by land “L” but it is to be understood that, dependingupon the particular towed sport to be carried out, surface 16 mayconsist of, or include, any combination or subcombination of liquidfreshwater or salt water, ice, snow, grass, concrete, asphalt, drylakebed, salt flats, dirt, mud, turf, artificial turf or other naturalor artificial surface(s). Again depending on the particular sportinvolved, surface 16 may optionally include or be provided with, or oneor more structures (not shown) which might serve for example asobstacles, boundary markers, or platforms for performing stunts ormaneuvers. Such optional structures might include for example, slalompoles, buoys, goal lines, distance markers, boundary markers, rampsand/or jumps (not shown).

For cable towed water skiing and cable towed wake boarding applications,support structures 12, 14 are tall enough to support a loop 44 of aflexible traction member 40, such as a steel cable, synthetic cable or adrive belt, such that a minimum clearance of approximately twenty feet(20 ft.) is maintained between the traction member 40 and the surface 16when apparatus is installed on a given site. The first support structure12 and the second support structure 14 are preferably formed of steeland each include a pair of legs 79. Each leg 79 is made up of a pair ofmutually spaced side rails 75, 76 that extend generally parallel to oneanother and are connected to one another by a plurality evenly mutuallyspaced rungs 85 which extend between, and are oriented transversely of,the side rails 75, 76. The opposite ends of each of the rungs 85 arewelded, or otherwise suitably joined, to each side rail 75, 76 so thatin addition to serving as a structural supporting member, each leg 79forms a ladder that can be climbed by workers as an aid in the course oferecting and installing the apparatus 10. The legs 79 are also usefulfollowing installation of apparatus 10 as they can be climbed bypersonnel for purposes such as adjusting, maintaining and makingperiodic inspections of apparatus 10.

As illustrated in FIG. 3 as well as in FIGS. 5 and 7 first supportstructure 12 and second support structure 14 are erected such that theirrespective pairs of legs 79 are relatively widely spaced from oneanother at their lower ends. Legs 79 angle toward one another and aremechanically coupled to one another at or near their upper ends suchthat support structure 12 takes the form of an A-frame tower 82 andsupport structure 14 takes the form of an elevated A-frame tower 83. Byway of non-limiting example, in the case of A-frame towers 82, 83 havinglegs 79 approximately twenty one feet (21 ft.) in length, the lower endsof the legs 79 of each tower would typically be spaced about ten feet(10 ft.) apart.

Optionally but preferably, A-frame towers 83, 85 each include at leastone brace member 84 extending between its legs 79 to maintain a theangle between the legs 79 substantially fixed when apparatus 10 isinstalled. To enhance the portability and compact storage of supportstructures 12, 14 when not in use, brace members 84 are preferablysecured to legs 79 removably, such as by use of removable bolts andnuts, preferably the type of nuts which include plastic inserts toresist inadvertent loosening. Alternatively, as illustrated in FIG. 5, acentral portion of brace member 84 may optionally provided with anarticulable joint 86 which can be latched open when apparatus 10 is inuse or unlatched to allow brace member 84 to fold so that both legs 79can be drawn close to one another for even more compact transportationand storage.

Although support structures 12, 14 could alternatively be constructed asfree-standing structures mounted removably or permanently uponfoundations designed appropriately for local soil conditions, thesupport structures 12, 14 of the preferred embodiment may rest directlyon top of the ground, either on dry land or partially submerged, aslocal soil conditions and topography will permit. Support structures 12,14 are preferably anchored in place by one or more guy lines 61, 62,which may suitably comprise steel cables. Guy lines 61, 62 arepreferably connected at or near the tops of the respective supportstructures 14, 12 at two locations via a wire rope harness 68, 69 usingshackles 70 as shown. Each guy line 61, 62 is then connected to ananchor 63, 64 on the ground. In the Figs. anchors 63, 64 are illustratedschematically as stakes driven into the ground. While stakes may besuitable for certain applications, it is to be understood that localsoil conditions may require use of any of various other forms of anchorswhich will be familiar to those skilled in the art, such as anchorsconsisting of buried plates and/or masses of reinforced concrete. Theguy lines 61, 62 are preferably positioned rearwardly and sidewardly ofsupport structures 12, 14 to help effectively resist static and dynamicforces such as those due to wind and those exerted on support structures12, 14 by way of traction member 40. Guy lines 61, 62 thus serve tofurther stabilize the support structures 12, 14 and secure them in placein an upright orientation and without excessive sway or other undesiredmovement.

The lower terminal end of each leg 79 of each support structure 12, 14may optionally be fitted with a base 88 from whose underside extends oneor more pointed, generally downwardly directed ground lugs or cleats 87.The bases 88 provide increased bearing surface area over which thedownward forces exerted by support structures 12, 14 can be distributedto the underlying substrates on which they are installed to provideadditional stability and to help prevent excessive sinking or tilting ofthe support structures 12, 14. The lugs or cleats 87 may suitably bewelded to the underside of base 88 and dig into the underlying earth orother substrate as further aid in preventing undesired movement of thesupport structures 12, 14 by providing them additional support,stability and ground bearing. As can be seen in FIGS. 5 and 7, the bases88 are preferably mounted so as to be capable of pivoting in twodirections in order to better facilitate the stable installation ofstructures 12, 14 on terrain or other substrate which may be somewhatuneven.

As shown in FIGS. 3 and 8, motive power for towing a sports participant120 is provided by a drive 19 which includes an electric motor 20 whichis mounted to a mounting bracket 18 affixed to the tops of the legs 79of the first support structure 12. Electric motor 20 is preferably areversible, variable-speed A.C. or D.C. motor which is disconnectablyelectrically coupled to a suitable electrical power source (not shown).Motor 20 is driveably mechanically coupled a substantially verticallyoriented drive pulley 22 by way of a gearbox 23. Drive pulley 22 ismounted for rotation about a rotational axis 37 between a pair ofmutually spaced vertical plates 48. The bottom edges of plates 48 arewelded to bracket 18 while their upper ends are secured by a cap plate90. Optionally, a clutch 24 may be interposed between pulley 22 andgearbox 23. For additional safety, clutch 24 may be of a type whichdisengages when a predetermined torque limit is exceeded, and/or whenthe electrical current drawn by motor 20 exceeds a predetermined limit,such as in the event traction member 40 and/or pulley 22 become jammed.

As shown in FIGS. 3 and 9, a substantially vertically orienteddeflection pulley 30 is freely rotatably mounted atop the second supportstructure 14. A length 36 of traction member 40 runs over the twopulleys 22, 30 and forms a loop 44 having an upper leg 50 and a lowerleg 52 which span the two support structures 12, 14 and extend overheadof surface 16 in the region between pulleys 22 and 30.

Preferably, the two pulleys 22, 30 are mutually aligned with one anothersuch that their respective substantially vertical planes of rotation 97,98 are co-planar, or are at least substantially co-planer. Also, therespective substantially horizontal rotational axes 37, 38 of the twopulleys 22, 30 are preferably substantially parallel with one anotherand substantially co-planar with one another. Pulleys 22, 30 are bothpreferably oriented in substantially vertical planes and rotate aboutrespective substantially horizontal rotational axes 37, 38 so that upperleg 50 and lower leg 52 of traction member 40 lie in a common plane withone another that is substantially vertical. Most preferably, pulleys 22,30 both rotate in a common vertical plane and rotational axes 37, 38 liein a common plane and are both horizontal, or at least substantiallyhorizontal, so that upper leg 50 of loop lies directly vertically abovelower leg 52 at all points along their span under windless quiescentconditions when no participant is being towed. Pulleys 22 and 30 bothpreferably rotate in a vertical plane but can, if desired be tiltedslightly provided neither tilts more than about fifteen degrees (15°)below vertical and the relative angle between the planes of rotation ofthe two pulleys 22, 30 does not exceed about fifteen degrees (15°) andpreferably does not exceed about five degrees (5°). Most preferablyhowever, pulleys 22, 30 are always aligned with one another so therelative angle between their respective planes of rotation 97, 98 isalways zero or at least substantially zero.

Apparatus 10 further includes a carrier 55, which, in the type shown inFIG. 3 and illustrated in detail in FIG. 10, has an elongated body 54whose length is somewhat greater than the normal spacing distance whichseparates the upper leg 50 and lower leg 52 of traction member 40. Thelower portion of the body 54 is coupled, by way of a first freelyrotatable joint 66, to a cross bar 65 whose opposed ends each carry acoupling 58. The couplings 58 securely affix the crossbar 65 immovablyto each free end of the lower leg 52 of the traction member 40. Thelower end of the body 54 of carrier 55 terminates in a second freelyrotatable joint 58 which includes a coupling 67 to which the upper endof a tow line 26 is securely affixed.

As FIG. 10 shows, the upper end of the body 54 of carrier 55 carries apair of freely rotatable rollers 56, 57 between which is routed theupper leg 50 of the traction member 40. The uppermost one of the tworollers, roller 56, includes a groove 76 which cooperates with the lowerroller 57 to keep upper leg 50 inside the groove 71 while allowingrollers 56, 57 to roll freely along upper leg 50. Rollers 56, 57 allowcarrier 55 to be pulled freely along upper leg 50 at the same speed anddirection as the lower leg 52 to which the carrier 55 is fixedlycoupled. Rollers 56, 57 further assure that the upper end of the carrier55 does not fall away from the upper leg 50, but can at all times movelinearly relative to the upper leg 50. A tow line 26 the lower end ofwhich may be fitted with a handle 28 is connected to the lower end ofcarrier 55 to tow sport participant 120 using the apparatus 10 as thecarrier 55 is driven by tension on the lower leg 52 of traction member40 produced in response to rotation of drive pulley 40 by drive 19.

FIGS. 12 and 13 illustrate an alternative carrier 55′ which may be usedin lieu of the carrier 55 described above. Carrier 55′ has a body 121which is comprised of a pair of mutually spaced, generally triangularplates 122, 123. A grooved roller 124 is freely rotatably mounted on ashaft 125 extending between the plates 122, 123 near their corners. Apair of rollers 126, 127 roll freely against roller 124 allowing thecarrier 55′ to roll above the upper leg 50 of traction member 40. Eachof the two lower corners of body 121 carry a generally cylindricalbumper 129. Each bumper 129 is preferably formed of a relatively hardsynthetic rubber material and includes a passage 130 through which arespective one of the end portions of the lower leg 52 of tractionmember 40 is received as shown. At a location intermediate the twobumpers 129, a bolt 133 having an unthreaded shank 134 passes throughboth plates 122 and 123 and is secured by a nut 135. A pair ofoppositely directed wedge clamps 137, 138 are freely pivotably mountedon shank 134. The end portions of the lower leg 52 are firmly secured tocarrier 55′ by wedge clamps 137. Attachment of a tow line 26 toalternate carrier 55′ is facilitated by an attachment ring 145 which, inorder to reduce the risk of twisting and kinking of the tow line 26, iscoupled by way of a swivel 147 to a U-bolt 148 which is suspended onshank 134.

The apparatus 10 is driven by electric motor 20, which is controlled bya motor controller 124 housed in control panel 98. If desired, the motorcontroller 124 can be pre-programmed or can be operated manually by oneperson who can simply push a start and stop button 97 and adjust a speedcontrol adjuster 99 on the control panel 98. This control panel 98 ispreferably located on or near a starting location, where participants120 take their turn being towed. Any suitable speed profile for carrier55 or 55′ such as for example one as illustrated in FIG. 11, can bepre-programmed into the motor controller 24 in the control panel 98.Alternatively, a person, even the participant themselves, can controlthe instantaneous speed and direction of the carrier 55 by controllingmotor 20 through a wired or wireless remote control unit 100 which canbe a handheld unit 100 which communicates with motor controller 24 byway of a wired or wireless communication link 102 such as a radiofrequency or microwave communication link.

As an option which may be particularly desirable when a remote controlunit 100 is used to control the velocity of carrier 55 or 55′,controller 124 may be programmed to provide a set or variable delaybetween a change a control input and the resulting actual change in thespeed and/or direction of carrier 55 or 55′.

To reduce the risk of carrier 55 or 55′ and or the tow line 26 frombecoming jammed or wrapped around drive pulley 22 and/or deflectionpulley 30, mechanical guards 42 are preferably mounted in front of eachpulley 22, 30 to provide a physical barrier interposed between eachpulley 22, 30 and carrier 55 or 55′ as shown in FIGS. 8 and 9.

In a first mode of operation, the carrier 55 or 55′ slows to asubstantially complete stop allowing the participant to disembark aftertaking a one way ride. In response to the powered rotation of drivepulley 22 and the resulting tension on lower leg 52, rollers 124, 126and 127 allow alternative carrier 55′ to be pulled freely along upperleg 50 at the same speed and in the same direction as lower leg 52. Theparticipant 120 may start from a standstill at an arbitrary locationwithin reach of towline 26. Motor controller 124 energizes drive 19 tocause motor 20 to begin rotating in a first rotational direction at aspeed which increases at a rate which may be varied as desired. Motor 20causes drive pulley 22 to rotate, which in turn drives the carrier 55 or55′ in a first direction along loop 55, pulling the participant 120behind at a corresponding speed and direction. If desired, controller124 may cause the speed of the carrier 55 or 55′ to increase or decreaseone or more times in each instance at any desired rate, beforedecreasing as the participant approaches an arbitrary stopping point orturning point.

In a second mode of operation of apparatus 10, a ride may begin as inthe first mode of operation described above but instead of stoppingafter a one way ride, the controller 124 causes carrier 55 or 55′ toslow or stop for a dwell interval sufficient to allow the participant120 to execute a turn, then the controller 124 begins driving the drivepulley 22 and thus the carrier 55 or 55′ in the opposite direction,accelerating at a desired rate, to pull the participant 120 in theopposite direction, back toward the starting location. After executingany desired intermediate changes in speed, carrier 55 or 55′ is thendecelerated to allow the participant to quit the ride at or near thelocation from which the ride started.

In a third illustrative mode of operation, apparatus 10 may be towedback and forth, reversing directing two or more times, each reversalbeing preceded by a dwell interval during which the carrier 55 or 55′either remains completely stopped, or does not exceed a maximum limitbefore the dwell interval ends. Reversals of direction of the carrier 55or 55′ can take place at locations corresponding to the maximum desiredextreme limits of its travel or can take place at any arbitrarylocations between those limits. Likewise, changes in speed and/oracceleration of carrier 55 or 55′ can be carried out in any safe mannerat any location intermediate the extremes of travel of the carrier 55,55′. Thus, a continuous non-stop ride of virtually arbitrary durationmay be enjoyed by the participant 120.

The participant 120 is towed back and forth between two supportstructures 12, 14 via the overhead running cable 40. For wakeboarding,the participant 120 holds the tow line 26 by way of a handle 28, whichmay be similar to the ropes used by water-skiers behind a boat. The towline 26 is connected to carrier 55 or 55′ that is attached to the lowerleg 52 of the loop 44 formed by traction member 40. As the cable 40 istowed by carrier 55 back and forth over at least a portion of thesurface 16 between the two support structures 12, 14. The participant120 can ski, wakeboard, kneeboard, ride an inner tube or otherinflatable device, wake skate, or the like. As the participant 120approaches one of the support structures 12, 14, the carrier 55 or 55′stops or at least slows for an interval and thereafter reversesdirection, so the participant 120 can make a turn and go back in theopposite direction. The traction member 40 and thus carrier 55 or 55′travel in one direction and then slow or pause for a dwell interval,illustrated as intervals I₁, I₂ and I₃ in FIG. 11, allowing theparticipant 120 time to make a sweeping turn as they keep tension on thetow line 26, and return in the other direction. It is to be noted thatdwell intervals I₁, I₂ and I₃ etc. can be of either fixed or variableduration and may, if desired be varied during the course of a ride.

While the invention has been described with reference to a preferredembodiment, it should be understood by those skilled in the art thatvarious changes may be made and equivalents substituted for elementsthereof without departing from the scope of the invention. In addition,many modifications may be made to adapt a particular situation ormaterial to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include all embodiments falling within the scope of the appendedclaims.

1. A towed sports apparatus for towing a sports participant over asurface, said apparatus, comprising: a first support structure and asecond support structure, said first support structure and said secondsupport structure being mutually separated from one another by at leasta portion of the surface over which the participant is to be towed; afirst pulley supportably mounted to said first support structure, saidfirst pulley being mounted for rotation in a first substantiallyvertical plane about a first substantially horizontal rotational axis; asecond pulley supportably mounted to said second support structure, saidsecond pulley being mounted for rotation in a second substantiallyvertical plane about a second substantially horizontal rotational axis;a flexible traction member driveably coupled said first pulley and saidsecond pulley to form an elongated loop having upper leg and a lowerleg, said upper leg extending between an upper portion of said firstpulley and an upper portion of said second pulley and said lower legbeing suspended between said first support structure and said secondsupport structure, at least a portion of said upper leg and said lowerleg passing overhead of said portion of said surface; a drive coupled tosaid loop by way of at least one of said first pulley and said secondpulley, for selectively driving said elongated loop in either a firstrotational direction or a second rotational direction and effecting saidrotation of said first pulley about said first substantially horizontalrotational axis and effecting said rotation of said second pulley aboutsaid second substantially horizontal rotational axis; a carrier mountedto said elongated loop with for travel along at least a portion of saidelongated loop, said carrier travelling in a first linear direction inresponse to said driving of said elongated loop in said first rotationaldirection and travelling in a second linear direction in response tosaid driving of said elongated loop in said second rotational direction,and a tow line having an upper end coupled to said carrier and a lowerend for towing the participant.
 2. An apparatus according to claim 1,wherein at least one of said first support structure and said secondsupport structure comprises a tower having a pair of legs which form anA-frame tower.
 3. An apparatus according to claim 2, wherein saidA-frame tower comprises at least one brace member connected between saidlegs.
 4. An apparatus according to claim 2, wherein at least one of saidlegs comprises a pair of side rails which are connected to one anotherby way of a plurality of mutually spaced rungs to form a ladder.
 5. Anapparatus according to claim 2, further comprising at least one guy linecoupled between said tower and an anchor location for stabilizing saidtower.
 6. An apparatus according to claim 1, wherein said drivecomprises a motor.
 7. An apparatus according to claim 4, wherein saiddrive further comprises a gearbox operably interposed between said motorand said first pulley.
 8. An apparatus according to claim 4, whereinsaid drive further comprises a clutch operably interposed between saidmotor and said first pulley.
 9. An apparatus according to claim 1,wherein said first substantially vertical plane and said secondsubstantially vertical plane are substantially co-planar with oneanother.
 10. An apparatus according to claim 1, wherein said firstsubstantially vertical plane is a plane which deviates from vertical byno more than about fifteen degrees.
 11. An apparatus according to claim1, wherein said first substantially vertical plane is a plane whichdeviates from vertical by more than about five degrees.
 12. An apparatusaccording to claim 1, wherein said second substantially vertical planeis a plane which deviates from vertical by more than about fifteendegrees.
 13. An apparatus according to claim 1, wherein said secondsubstantially vertical plane is a plane which deviates from vertical bymore than about five degrees.
 14. An apparatus according to claim 1,wherein said first substantially vertical plane and said secondsubstantially vertical plane are tilted relative to one by more thanabout fifteen degrees.
 15. An apparatus according to claim 1, whereinsaid first substantially vertical plane and said second substantiallyvertical plane are not tilted relative to one another by more than aboutfive degrees.
 16. A method for towing a sport participant over asurface, said method comprising the steps of: forming a flexibletraction member into a loop extending drivably between a first pulleyand a second pulley, said first pulley being mounted for rotation in afirst substantially vertical plane, said second pulley being mounted forrotation in a second substantially vertical plane, at least a portion ofsaid loop extending above said surface; coupling a tow line to saidloop; rotatably driving at least one of said first pulley and saidsecond pulley to cause said loop to rotate; and towing said participantover said surface by way of said tow line.
 17. The method of claim 16further comprising the step of controlling said rotatable drivingaccording to a velocity profile which includes at least one increase andat least one decrease in rotational speed.
 18. The method of claim 17wherein said velocity profile further includes at least one reversal ofdirection of said rotatable driving of said loop.
 19. The method ofclaim 18 wherein each said reversal of direction is preceded by a dwellinterval during which a speed of rotation of said loop is maintainedbelow a limit.